Expander for brakes and clutches



Och 7, 1.952 R, 1 KELLER 2,612,909

EXPANDER FOR BRAKES AND CLUTCHES FiledNov. 23, 194e iff/@ Patented Oct. 7, 1952 UNITED f vs'rAri:

S PATE Nr OFFICE" B. F. Goodrich Company, New corporation of New York York,` N. Y., a

Application November Z3, 1946, Serial No. 711,947

This invention relates to expanders for brakes,

clutches and `the like and to themanufacture` thereof.

It is an object of the present invention to form an endless annular expander tube with a molded inner surface.

Other objects are `to provide an expander tube having walls of uniform shape along the length thereof, to provide a tube with smoothly rounded cavity margins, to provide a tube having a` minimum capacity forinlation fluid in its collapsed condition, to provide for improved flexing action at the margins of thetube cavity, to provide a` core-molded cavity surface, and to provide for improved retention of the tube in itsv supporting channel.

These and other objects will appear from the the I accompanying Fig. 3 is a cross-section thereof on line 3-3 of Fig. 1, and

Fig. 4 is a perspective view of a portion of the mandrel or core.

Referring to I the drawings, the numeral Ill designates a brake supporting drum formed with a channel for supporting an expander tube I2v and a set of Vbrake shoes I3 in opposed relation to a reaction member I5. The brake shoesmay be of moldedmaterial having a high coeillcient of friction and heat resisting properties such as molded brake lining material. Each shoe is grooved as at I6V at its ends to engage over fiat retractor springs I'I` whichmay have their ends seated in the side walls of the brake channel for resisting torque.` I I The expander `tube I2 has an annular core I8 in the'form of a band having thickened beaded lateral margins I9, 20 separated by thinner portions 2| of uniform thickness. The core is preferably of stiff material such as hard or semi-hard rubber compound and is not adhered to the tube which surrounds it, at least in the radially outward portions. The tube I2 at its interior closely conforms to the core in shape and dimension in its deflated condition and is Vmade of elastic resilient rubber or other rubber-like material. Itv

l For clearing the flange 28 of the valve stem, 'an opening 21 is formed through the core I8. The 'arrangement isfsuch that in the deflated position of the tube, the tube cavity is closedtby contact of the tube with the core except forthe clearance area` about the flange 26 within the opening 2l providing "a tube'of minimum capacity in the deflated `position shown in Fig. 2; In the inflated position shown in Fig. 3 the outer wall of the tube is separated from-the `core by the fluid pressure. A further advantage of this construction lies in the fact that yno sharp flexure or creasing of thetube at the margins of the cavity is required to close the tube completely. I In constructing the expander tube the core IB is molded and preferably at least` partially vulcanized. `The opening 21 may be formed therethrough by molding or may befformed by drilling or punching the ilnished core. Material is then wound about the core in sheet form and conformed to the surface of the core `after which the core with the material thereabout may be `vulcanized in a mold or in open steam as desired. The core acts to shape the inside of the tube to the desired shape and size in addition to serving its purposes in the completed tube.

In order to provide for high lift of the brake Vshoes without excessive stretch of thewalls of the `tube at its `margins it is desirable to form the inflatable cavity with radially outwardly `turned portions at the marginal walls. To provide against cracking of the tube under the stress of inflation it is also desirable to avoid sharp `corners and to provide smoothly curved walls at the lateral margins of the cavity. Theseresults are accomplished uniformly v,by Vprovision of the core I 8 which controls the molding of the cavity during manufacture, and thereafter acts to hold the tube in place against undesirable dislodgment, and to reduce the space for trapping inating liquid due to displacementthereof without requiring sharp creasing of .the tube walk.

Variations may be made' without departing from the scope of the invention as it is defined by thefollowing claims. l I

I claim: t l An expander for applying pressure to a brake or the like, said expander comprising normally flat annular body of` rubber-like material having a circumferential fluid-receiving cavity thereinpand an annular"`core within said cavity, said core comprising a band of stiff material having beaded lateral margins and an outer peripheral surface therebetween depressed below said margins, said body having a radially displaceable surface substantially complementary to and closely conforming to and contactn iiuid, and means on said bodyfor supplying nuid under pressure to said duid-receiving cavity.`

2. An expander for applying pressure to a brake or. the like, said expander comprising a normally nat annular body of rubber-like material having a circumferential fluid-receiving cavity therein, and an annular'core within said cavity, said core comprising a band of stiff rmaterial having a central annular Zone generally flat in cross-section and annular margins extending radially outward thereof and anking said zone, said body having a radially displaceable surface substantially complementary to and -closely conforming to andcontacting said core I, v.throughout its peripheral surface inthe deated unstrained condition of ,the expander and. separable `from said core in the radial direction by inflating pressure of the:A expander iiui-d, and

.conforming to .and contactingsaid' core throughout its peripheral surface in the deiiated unstrained condition. of the expander and separable Vform said core in .the radial-direction by inflating pressure of. the` expander fluid .and an outer braking face substantially fiat incross section, and means on said. body for supplying fluid under pressure to said fluid-receiving. cavity.

4. An expander for radially engageable brakes and clutches, said expander vcomprising an 4endless band-like expander tube of elastic material having radially inner land outer walls united at their lateral margins and deiining a circumferential cavity therebetween, the 'outer :wall thereof being expansible radially outward by iiuid pressure Within saidV cavity, a relatively stiff :endless band core within said cavity separating said inner and outer walls .of the expander' ytube by contact therewith and holding vthe'irmer wall against forcestending to move it ina radially-outward direction by virtuef of the stiff nature of said band core Vwhile permitting movement of the outer wall ofthe expander tube-radially outward, and means onsaid tube .for supplying. iluidunder pressure to 'said' cavity.

' 5'. A fluid-operated expander'torapplyingpressure to a brake or the like comprising -agresilient impervious envelope having opposed operating and back Walls united at their margins and defining between them an inflation. cavity having an intermediate portion and marginal portions depressed intofthe operating wall with respect to said intermediate portion of the cavity providing for increased displacement. of said operating wal-1 with respect to thev back wall by virtue of. the marginal depressed portionsy of the cavity, a core within said cavity separating the walls thereof by contact therewith when said cavity is deated and having an intermediate.portionandmarginal portions substantially conforming to said cavity including the depressed marginal portions thereof, said operating wall bei-ng separable. from. said core upon inflation, and means on said envelope .for supplying. iiuid under pressure to said cavity.

'5. An'expander for'applying pressure to a brake or the like, said expander comprising an annular band of stiif materialhaving beaded lateral margins, an annular expander tube of resilient rubber-like material Yhaving a cavity extending cirkcurnierentially thereof and closely conforming to the contacting said band throughout its peripheral surface in the unstrained deated position of .said tube,said .tube having peripherally inner and outer walls radially displaceable one relative lto the other and separated by said band, and means on said tube for supplying iiuid under -pressure .to said cavity..-

-'Z. Anexpander vforappl-yng pressure to a fluidoperated brake or the like, said expander comprising-an annular band of stiff material having beaded lateral. margins and an outer peripheral pleinen-tary to .and .closely contacting said band throughout its Vperiphery in the unstrained deiiated positionof said tube, including a pressure surfacey havin-gdepressed. margins conforming to vand .contacting the beaded margins and depressed surface of-said band, providing for extensive displacement of said surface of the tube relative. to the opposite .surface of the interior of the tube facilitated by said depressed margins, and means on said tube for supplying fluid under pressure to said tube.

8. An-.expander for applying pressure to a fluid operated brake .orthe like, said expander comprising an annular Y.body o-i resilient rubber-like material having a circumferential iluid receiving cavity thereinran annular core within said cavity, said body having an interior surface substantially complementary `to and .closely .contacting said core throughout its periphery in the unstrained deflated-position of. said body and separable from said core by the expander iiuid .Lmder pressure, and. meansonsaid body .for supplying fluid under pressure. to said `fluid-receiving cavity.

9.. Anexpander for applying pressure to a fluid operated .brake or the like, said expander comprising .anann-ular .body of rubber-like material havin-g a .circumferentialfluid-receiving cavity therein forming separate pressure surfaces of said cavity displaceable -one relative to the other in a radial direction, an- .annular core within said `cavity contacting thesurfaces thereof thereby to `support .th-esurfaces-cf said cavity in the deflated condition of the expander and separate said pressure surfaces-in the radial direction, and means on said body vfor supplying iiuid under pressure .to said. nuidfreoeiving cavity.

n, RUSSELL J. KELLER..

I REFERENCES CITED The following references are of record in the `rile of this `patent:l

.Y UNITED f STATES PATENTS 

